If Qunut is forgotten and remembered after reaching Ruku, what should the worshipper do?

Witr: Structure, Qunut, Missed Qunut, and Ramadan Congregation

• Do not return to the Qunut position; complete the prayer and perform Sujud al-Sahw.
• Return to standing, repeat the whole rak'ah, and omit Sujud al-Sahw.
• End the prayer immediately.
• Repeat the opening Takbir from the beginning.